Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| bioinformatics analysis of the locus for enterocyte effacement provides novel insights into type-iii secretion. | like many other pathogens, enterohaemorrhagic and enteropathogenic strains of escherichia coli employ a type-iii secretion system to translocate bacterial effector proteins into host cells, where they then disrupt a range of cellular functions. this system is encoded by the locus for enterocyte effacement. many of the genes within this locus have been assigned names and functions through homology with the better characterised ysc-yop system from yersinia spp. however, the functions and homologie ... | 2005 | 15757514 |
| the 'permeome' of the malaria parasite: an overview of the membrane transport proteins of plasmodium falciparum. | the uptake of nutrients, expulsion of metabolic wastes and maintenance of ion homeostasis by the intraerythrocytic malaria parasite is mediated by membrane transport proteins. proteins of this type are also implicated in the phenomenon of antimalarial drug resistance. however, the initial annotation of the genome of the human malaria parasite plasmodium falciparum identified only a limited number of transporters, and no channels. in this study we have used a combination of bioinformatic approach ... | 2005 | 15774027 |
| the many faces of protease-protein inhibitor interaction. | proteases and their natural protein inhibitors are among the most intensively studied protein-protein complexes. there are about 30 structurally distinct inhibitor families that are able to block serine, cysteine, metallo- and aspartyl proteases. the mechanisms of inhibition can be related to the catalytic mechanism of protease action or include a mechanism-unrelated steric blockage of the active site or its neighborhood. the structural elements that are responsible for the inhibition most often ... | 2005 | 15775973 |
| structure and biochemical analysis of a secretin pilot protein. | the ability to translocate virulence proteins into host cells through a type iii secretion apparatus (ttss) is a hallmark of several gram-negative pathogens including shigella, salmonella, yersinia, pseudomonas, and enteropathogenic escherichia coli. in common with other types of bacterial secretion apparatus, the assembly of the ttss complex requires the preceding formation of its integral outer membrane secretin ring component. we have determined at 1.5 a the structure of mxim28-142, the shige ... | 2005 | 15775974 |
| functional insights from the distribution and role of homopeptide repeat-containing proteins. | expansion of "low complex" repeats of amino acids such as glutamine (poly-q) is associated with protein misfolding and the development of degenerative diseases such as huntington's disease. the mechanism by which such regions promote misfolding remains controversial, the function of many repeat-containing proteins (rcps) remains obscure, and the role (if any) of repeat regions remains to be determined. here, a web-accessible database of rcps is presented. the distribution and evolution of rcps t ... | 2005 | 15805494 |
| lethal effect of the gliding arc discharges on erwinia spp. | to compare the decontamination performances of glidarc on strains of erwinia of industrial interest. | 2005 | 15836472 |
| autoinduction in erwinia amylovora: evidence of an acyl-homoserine lactone signal in the fire blight pathogen. | erwinia amylovora causes fire blight disease of apple, pear, and other members of the rosaceae. here we present the first evidence for autoinduction in e. amylovora and a role for an n-acyl-homoserine lactone (ahl)-type signal. two major plant virulence traits, production of extracellular polysaccharides (amylovoran and levan) and tolerance to free oxygen radicals, were controlled in a bacterial-cell-density-dependent manner. two standard autoinducer biosensors, agrobacterium tumefaciens ntl4 an ... | 2005 | 15838048 |
| three-dimensional structure of (1,4)-beta-d-mannan mannanohydrolase from tomato fruit. | the three-dimensional crystal structure of tomato (lycopersicon esculentum) beta-mannanase 4a (leman4a) has been determined to 1.5 a resolution. the enzyme adopts the (beta/alpha)(8) fold common to the members of glycohydrolase family gh5. the structure is comparable with those of the homologous trichoderma reesei and thermomonospora fusca beta-mannanases: there is a conserved three-stranded beta-sheet located near the n terminus that stacks against the central beta-barrel at the end opposite th ... | 2005 | 15840830 |
| structure of a full length psychrophilic cellulase from pseudoalteromonas haloplanktis revealed by x-ray diffraction and small angle x-ray scattering. | pseudoalteromonas haloplanktis is a psychrophilic gram-negative bacterium isolated in antarctica, that lives on organic remains of algae. this bacterium converts the cellulose, highly constitutive of algae, into an immediate nutritive form by biodegrading this biopolymer. to understand the mechanisms of cold adaptation of its enzymatic components, we studied the structural properties of an endoglucanase, cel5g, by complementary methods, x-ray crystallography and small angle x-ray scattering. usi ... | 2005 | 15854656 |
| imidazole antibiotics inhibit the nitric oxide dioxygenase function of microbial flavohemoglobin. | flavohemoglobins metabolize nitric oxide (no) to nitrate and protect bacteria and fungi from no-mediated damage, growth inhibition, and killing by no-releasing immune cells. antimicrobial imidazoles were tested for their ability to coordinate flavohemoglobin and inhibit its no dioxygenase (nod) function. miconazole, econazole, clotrimazole, and ketoconazole inhibited the nod activity of escherichia coli flavohemoglobin with apparent k(i) values of 80, 550, 1,300, and 5,000 nm, respectively. sacc ... | 2005 | 15855504 |
| the semi-phosphorylative entner-doudoroff pathway in hyperthermophilic archaea: a re-evaluation. | biochemical studies have suggested that, in hyperthermophilic archaea, the metabolic conversion of glucose via the ed (entner-doudoroff) pathway generally proceeds via a non-phosphorylative variant. a key enzyme of the non-phosphorylating ed pathway of sulfolobus solfataricus, kdg (2-keto-3-deoxygluconate) aldolase, has been cloned and characterized previously. in the present study, a comparative genomics analysis is described that reveals conserved ed gene clusters in both thermoproteus tenax a ... | 2005 | 15869466 |
| production of autoinducer 2 in salmonella enterica serovar thompson contributes to its fitness in chickens but not on cilantro leaf surfaces. | food-borne illness caused by salmonella enterica has been linked traditionally to poultry products but is associated increasingly with fresh fruits and vegetables. we have investigated the role of the production of autoinducer 2 (ai-2) in the ability of s. enterica serovar thompson to colonize the chicken intestine and the cilantro phyllosphere. a mutant of s. enterica serovar thompson that is defective in ai-2 production was constructed by insertional mutagenesis of luxs. the population size of ... | 2005 | 15870357 |
| prevalence of pathogenicity island iicft073 genes among extraintestinal clinical isolates of escherichia coli. | uropathogenic escherichia coli is the most common cause of urinary tract infection (uti). cystitis in women is by far the most common uti; pyelonephritis in both sexes and prostatitis in men are more severe but are less frequent complaints. the ability of e. coli to cause uti is associated with specific virulence determinants, some of which are encoded on pathogenicity islands (pai). one such pai (pai iicft073), of the prototypical uropathogenic e. coli strain cft073, contains 116 open reading f ... | 2005 | 15872276 |
| iron-sulfur cluster biogenesis in chloroplasts. involvement of the scaffold protein cpisca. | the chloroplast contains many iron (fe)-sulfur (s) proteins for the processes of photosynthesis and nitrogen and s assimilation. although isolated chloroplasts are known to be able to synthesize their own fe-s clusters, the machinery involved is largely unknown. recently, a cysteine desulfurase was reported in arabidopsis (arabidopsis thaliana; atcpnifs) that likely provides the s for fe-s clusters. here, we describe an additional putative component of the plastid fe-s cluster assembly machinery ... | 2005 | 15888686 |
| bordetella alcs transporter functions in alcaligin siderophore export and is central to inducer sensing in positive regulation of alcaligin system gene expression. | bordetella pertussis and bordetella bronchiseptica, which are respiratory mucosal pathogens of mammals, produce and utilize the siderophore alcaligin to acquire iron in response to iron starvation. a predicted permease of the major facilitator superfamily class of membrane efflux pumps, alcs (synonyms, orfx and bcr), was reported to be encoded within the alcaligin gene cluster. in this study, alcs null mutants were found to be defective in growth under iron starvation conditions, in iron source ... | 2005 | 15901687 |
| novel molecular features of the fibrolytic intestinal bacterium fibrobacter intestinalis not shared with fibrobacter succinogenes as determined by suppressive subtractive hybridization. | suppressive subtractive hybridization was conducted to identify unique genes coding for plant cell wall hydrolytic enzymes and other properties of the gastrointestinal bacterium fibrobacter intestinalis dr7 not shared by fibrobacter succinogenes s85. subtractive clones from f. intestinalis were sequenced and assembled to form 712 nonredundant contigs with an average length of 525 bp. of these, 55 sequences were unique to f. intestinalis. the remaining contigs contained 764 genes with blastx simi ... | 2005 | 15901698 |
| 1.6 a crystal structure of yter protein from bacillus subtilis, a predicted lyase. | 2005 | 15906318 | |
| a differential medium for the isolation and rapid identification of a plant soft rot pathogen, erwinia chrysanthemi. | a medium was developed for the isolation and differentiation of erwinia chrysanthemi from other erwinia spp. based on the production of blue-pigmented indigoidine. the medium, named ngm, consists of nutrient agar supplemented with 1% glycerol, that induces pigment production, and 2 mm mncl2*4h2o, that further enhances color development. more than fifty e. chrysanthemi strains from six different plant hosts were tested. all tested strains of e. chrysanthemi grew well on the ngm medium, developing ... | 2006 | 15927293 |
| evolutionary relationships of three new species of enterobacteriaceae living as symbionts of aphids and other insects. | ecological studies on three bacterial lineages symbiotic in aphids have shown that they impose a variety of effects on their hosts, including resistance to parasitoids and tolerance to heat stress. phylogenetic analyses of partial sequences of gyrb and reca are consistent with previous analyses limited to 16s rrna gene sequences and yield improved confidence of the evolutionary relationships of these symbionts. all three symbionts are in the enterobacteriaceae. one of the symbionts, here given t ... | 2005 | 15933033 |
| involvement of bacterial quorum-sensing signals in spoilage of bean sprouts. | bacterial communication signals, acylated homoserine lactones (ahls), were extracted from samples of commercial bean sprouts undergoing soft-rot spoilage. bean sprouts produced in the laboratory did not undergo soft-rot spoilage and did not contain ahls or ahl-producing bacteria, although the bacterial population reached levels similar to those in the commercial sprouts, 10(8) to 10(9) cfu/g. ahl-producing bacteria (enterobacteriaceae and pseudomonads) were isolated from commercial sprouts, and ... | 2005 | 15933035 |
| role of xcpp in the functionality of the pseudomonas aeruginosa secreton. | in gram-negative bacteria, most signal-peptide-dependent exoproteins are secreted via the type ii secretion system (t2ss or secreton). in pseudomonas aeruginosa, t2ss consists of twelve xcp proteins (xcpa and xcpp to xcpz) thought to be organized as a multiproteic complex within the envelope. although well conserved, t2ss are known to be species-specific, namely for distant organisms, and this characteristic was thought to involve xcpp. to check which domain of xcpp could be involved in the spec ... | 2005 | 15936176 |
| pseudomonas syringae type iii chaperones shco1, shcs1, and shcs2 facilitate translocation of their cognate effectors and can substitute for each other in the secretion of hopo1-1. | the pseudomonas syringae type iii secretion system (ttss) translocates effector proteins into plant cells. several p. syringae effectors require accessory proteins called type iii chaperones (ttcs) to be secreted via the ttss. we characterized the hopo1-1, hops1, and hops2 operons in p. syringae pv. tomato dc3000; these operons encode three homologous ttcs, shco1, shcs1, and shcs2. shco1, shcs1, and shcs2 facilitated the type iii secretion and/or translocation of their cognate effectors hopo1-1, ... | 2005 | 15937188 |
| unraveling the secret lives of bacteria: use of in vivo expression technology and differential fluorescence induction promoter traps as tools for exploring niche-specific gene expression. | a major challenge for microbiologists is to elucidate the strategies deployed by microorganisms to adapt to and thrive in highly complex and dynamic environments. in vitro studies, including those monitoring genomewide changes, have proven their value, but they can, at best, mimic only a subset of the ensemble of abiotic and biotic stimuli that microorganisms experience in their natural habitats. the widely used gene-to-phenotype approach involves the identification of altered niche-related phen ... | 2005 | 15944455 |
| cloning, expression and characterisation of erwinia carotovora l-asparaginase. | bacterial l-asparaginases (e.c. 3.5.1.1) have been used as therapeutic agents in the treatment of acute childhood lymphoblastic leukaemia. l-asparaginase from erwinia carotovora ncyc 1526 (era) was cloned and expressed in e. coli. the enzyme was purified to homogeneity by a two-step procedure comprising cation-exchange chromatography and affinity chromatography on immobilised l-asparagine. the enzymatic properties of the recombinant enzyme were investigated and the kinetic parameters (k(m), k(ca ... | 2005 | 15951039 |
| mechanisms of protein export across the bacterial outer membrane. | 2005 | 15968039 | |
| epimerase active domain of pseudomonas aeruginosa algg, a protein that contains a right-handed beta-helix. | the polysaccharide alginate forms a protective capsule for pseudomonas aeruginosa during chronic pulmonary infections. the structure of alginate, a linear polymer of beta1-4-linked o-acetylated d-mannuronate (m) and l-guluronate (g), is important for its activity as a virulence factor. alginate structure is mediated by algg, a periplasmic c-5 mannuronan epimerase. algg also plays a role in protecting alginate from degradation by the periplasmic alginate lyase algl. here, we show that the c-termi ... | 2005 | 15968068 |
| flavohaemoglobin hmpx from erwinia chrysanthemi confers nitrosative stress tolerance and affects the plant hypersensitive reaction by intercepting nitric oxide produced by the host. | host cells respond to infection by generating nitric oxide (no) as a cytotoxic weapon to facilitate killing of invading microbes. bacterial flavohaemoglobins are well-known scavengers of no and play a crucial role in protecting animal pathogens from nitrosative stress during infection. erwinia chrysanthemi, which causes macerating diseases in a wide variety of plants, possesses a flavohaemoglobin (hmpx) whose function in plant pathogens has remained unclear. here we show that hmpx consumes no an ... | 2005 | 15998309 |
| siderophore-mediated upregulation of arabidopsis ferritin expression in response to erwinia chrysanthemi infection. | ferritins are multimeric iron storage proteins encoded by a four-member gene family in arabidopsis (atfer1-4). to investigate whether iron sequestration in ferritins is a part of an iron-withholding defense system induced in response to bacterial invasion, we used arabidopsis thaliana as a susceptible host for the pathogenic bacterium erwinia chrysanthemi. in this study, we used a t-dna insertion mutant line to show that the lack of a functional atfer1 gene resulted in an enhanced susceptibility ... | 2005 | 15998312 |
| ousb, a broad-specificity abc-type transporter from erwinia chrysanthemi, mediates uptake of glycine betaine and choline with a high affinity. | the ability of erwinia chrysanthemi to cope with environments of elevated osmolality is due in part to the transport and accumulation of osmoprotectants. in this study we have identified a high-affinity glycine betaine and choline transport system in e. chrysanthemi. by using a pool of tn5-b21 ousa mutants, we isolated a mutant that could grow in the presence of a toxic analogue of glycine betaine (benzyl-glycine betaine) at high osmolalities. this mutant was impaired in its ability to transport ... | 2005 | 16000740 |
| transfer of pectobacterium chrysanthemi (burkholder et al. 1953) brenner et al. 1973 and brenneria paradisiaca to the genus dickeya gen. nov. as dickeya chrysanthemi comb. nov. and dickeya paradisiaca comb. nov. and delineation of four novel species, dickeya dadantii sp. nov., dickeya dianthicola sp. nov., dickeya dieffenbachiae sp. nov. and dickeya zeae sp. nov. | a collection of 75 strains of pectobacterium chrysanthemi (including all biovars and pathovars) and the type strains of brenneria paradisiaca (cfbp 4178(t)) and pectobacterium cypripedii (cfbp 3613(t)) were studied by dna-dna hybridization, numerical taxonomy of 121 phenotypic characteristics, serology and 16s rrna gene-based phylogenetic analyses. from analysis of 16s rrna gene sequences, it was deduced that p. chrysanthemi strains and b. paradisiaca cfbp 4178(t) formed a clade distinct from th ... | 2005 | 16014461 |
| mutation of the zinc-binding metalloprotease motif affects bacteroides fragilis toxin activity but does not affect propeptide processing. | to evaluate the role of the zinc-binding metalloprotease in bacteroides fragilis toxin (bft) processing and activity, the zinc-binding consensus sequences (h348, e349, h352, g355, h358, and m366) were mutated by site-directed-mutagenesis. our results indicated that single point mutations in the zinc-binding metalloprotease motif do not affect bft processing but do reduce or eliminate bft biologic activity in vitro. | 2005 | 16041055 |
| comparison of the complete genome sequences of pseudomonas syringae pv. syringae b728a and pv. tomato dc3000. | the complete genomic sequence of pseudomonas syringae pv. syringae b728a (pss b728a) has been determined and is compared with that of p. syringae pv. tomato dc3000 (pst dc3000). the two pathovars of this economically important species of plant pathogenic bacteria differ in host range and other interactions with plants, with pss having a more pronounced epiphytic stage of growth and higher abiotic stress tolerance and pst dc3000 having a more pronounced apoplastic growth habitat. the pss b728a ge ... | 2005 | 16043691 |
| the in situ observation of the temperature and pressure stability of recombinant aspergillus aculeatus pectin methylesterase with fourier transform ir spectroscopy reveals an unusual pressure stability of beta-helices. | the stability of recombinant aspergillus aculeatus pme (pectin methylesterase), an enzyme with high beta-helix content, was studied as a function of pressure and temperature. the conformational stability was monitored using ftir (fourier transform ir) spectroscopy whereas the functional enzyme stability was monitored by inactivation studies. protein unfolding followed by amorphous aggregation, which makes the process irreversible, was observed at temperatures above 50 degrees c. this could be co ... | 2005 | 16050809 |
| parallel beta-sheets and polar zippers in amyloid fibrils formed by residues 10-39 of the yeast prion protein ure2p. | we report the results of solid-state nuclear magnetic resonance (nmr) and atomic force microscopy measurements on amyloid fibrils formed by residues 10-39 of the yeast prion protein ure2p (ure2p(10)(-)(39)). measurements of intermolecular (13)c-(13)c nuclear magnetic dipole-dipole couplings indicate that ure2p(10)(-)(39) fibrils contain in-register parallel beta-sheets. measurements of intermolecular (15)n-(13)c dipole-dipole couplings, using a new solid-state nmr technique called dsq-redor, are ... | 2005 | 16060675 |
| the bacteriophage p1 hot gene product can substitute for the escherichia coli dna polymerase iii {theta} subunit. | the theta subunit (hole gene product) of escherichia coli dna polymerase (pol) iii holoenzyme is a tightly bound component of the polymerase core. within the core (alpha-epsilon-theta), the alpha and epsilon subunits carry the dna polymerase and 3' proofreading functions, respectively, while the precise function of theta is unclear. hole homologs are present in genomes of other enterobacteriae, suggestive of a conserved function. putative homologs have also been found in the genomes of bacteriop ... | 2005 | 16077097 |
| structure of bacterial extracellular polymeric substances at different ph values as determined by saxs. | extracellular polymeric substances (eps) play an important role in cell aggregation, cell adhesion, and biofilm formation, and protect cells from a hostile environment. the eps was isolated by trichloroacetic acid/ethanol extraction from broth culture of a marine bacterium isolate. the eps was composed of glucose and galactose as determined by hplc and tlc; the protein content was on average 15 +/- 5% of eps dry mass. the solution structure of eps at different values of ph was revealed by small- ... | 2005 | 16085763 |
| characterization of an unusual cold-active beta-glucosidase belonging to family 3 of the glycoside hydrolases from the psychrophilic isolate paenibacillus sp. strain c7. | we selected for spore-forming psychrophilic bacteria able to use lactose as a carbon source and one isolate, designated paenibacillus sp. strain c7, that was phylogenetically related to, but distinct from both paenibacillus macquariensis and paenibacillus antarcticus. some escherichia coli transformants obtained with genomic dna from this isolate hydrolyzed x-gal (5-bromo-4-chloro-3-indoyl-beta-d-galactopyranoside) only below 30 degrees c, an indication of cold-active beta-galactosidase activity ... | 2005 | 16085807 |
| mycosubtilin overproduction by bacillus subtilis bbg100 enhances the organism's antagonistic and biocontrol activities. | a bacillus subtilis derivative was obtained from strain atcc 6633 by replacement of the native promoter of the mycosubtilin operon by a constitutive promoter originating from the replication gene repu of the staphylococcus aureus plasmid pub110. the recombinant strain, designated bbg100, produced up to 15-fold more mycosubtilin than the wild type produced. the overproducing phenotype was related to enhancement of the antagonistic activities against several yeasts and pathogenic fungi. hemolytic ... | 2005 | 16085851 |
| elevated temperature enhances virulence of erwinia carotovora subsp. carotovora strain ec153 to plants and stimulates production of the quorum sensing signal, n-acyl homoserine lactone, and extracellular proteins. | erwinia carotovora subsp. atroseptica, e. carotovora subsp. betavasculorum, and e. carotovora subsp. carotovora produce high levels of extracellular enzymes, such as pectate lyase (pel), polygalacturonase (peh), cellulase (cel), and protease (prt), and the quorum-sensing signal n-acyl-homoserine lactone (ahl) at 28 degrees c. however, the production of these enzymes and ahl by these bacteria is severely inhibited during growth at elevated temperatures (31.2 degrees c for e. carotovora subsp. atr ... | 2005 | 16085860 |
| the family of serratia type pore forming toxins. | the serratia marcescens hemolysin represents the prototype of a growing family of pore forming toxins. the available bacterial genome sequences reveal serratia hemolysin homologues in additional species. however, only s. marcescens hemolysin has been studied in great molecular detail. this family of toxins has nothing in common with the pore forming toxins of e. coli type (rtx toxins), the staphylococcus aureus alpha-toxin or the thiol activated toxin of group a beta-hemolytic streptococci (stre ... | 2005 | 16101433 |
| identification of the mycobacterium tuberculosis suf machinery as the exclusive mycobacterial system of [fe-s] cluster assembly: evidence for its implication in the pathogen's survival. | the worldwide recrudescence of tuberculosis and widespread antibiotic resistance have strengthened the need for the rapid development of new antituberculous drugs targeting essential functions of its etiologic agent, mycobacterium tuberculosis. in our search for new targets, we found that the m. tuberculosis pps1 gene, which contains an intein coding sequence, belongs to a conserved locus of seven open reading frames. in silico analyses indicated that the mature pps1 protein is orthologous to th ... | 2005 | 16109955 |
| [purification and properties of recombinant erwinia carotovora l-asparaginase expressed in e.coli cells]. | the method of purification erwinia carotovora recombinant l-asparaginase, expressed in e.coli, including ultrasonic disintegration of biomass, fractionation ammonium sulfate and column chromatography on cm- or sp-sepharose has been developed. according to sds-paage the enzyme preparation was homogeneous, its specific activity and yield consist respectively about 620 iu/mg of protein and 75%. physical-chemical and structural properties of recombinant erwinia carotovora l-asparaginase are similar ... | 2003 | 16119104 |
| replication termination in escherichia coli: structure and antihelicase activity of the tus-ter complex. | the arrest of dna replication in escherichia coli is triggered by the encounter of a replisome with a tus protein-ter dna complex. a replication fork can pass through a tus-ter complex when traveling in one direction but not the other, and the chromosomal ter sites are oriented so replication forks can enter, but not exit, the terminus region. the tus-ter complex acts by blocking the action of the replicative dnab helicase, but details of the mechanism are uncertain. one proposed mechanism invol ... | 2005 | 16148308 |
| purification and characterization of the n-terminal domain of exea: a novel atpase involved in the type ii secretion pathway of aeromonas hydrophila. | aeromonas hydrophila secretes a number of degradative enzymes and toxins into the external milieu via the type ii secretory pathway or secreton. exea is an essential component of this system and is necessary for the localization and/or multimerization of the secretin exed. exea contains two sequence motifs characteristic of the walker superfamily of atpases. previous examination of substitution derivatives altered in these motifs suggested that atp binding or hydrolysis is required for exeab com ... | 2005 | 16159770 |
| role of conserved cysteines in mediating sulfur transfer from iscs to iscu. | the role of the three conserved cysteine residues on azotobacter vinelandii iscu in accepting sulfane sulfur and forming a covalent complex with iscs has been evaluated using electrospray-ionization mass spectrometry studies of variants involving individual cysteine-to-alanine substitutions. the results reveal that iscs can transfer sulfur to each of the three alanine-substituted forms of iscu to yield persulfide or polysulfide species, and formation of a heterodisulfide covalent complex between ... | 2005 | 16165131 |
| gene products of the hupghij operon are involved in maturation of the iron-sulfur subunit of the [nife] hydrogenase from rhizobium leguminosarum bv. viciae. | in the present study, we investigate the functions of the hupghij operon in the synthesis of an active [nife] hydrogenase in the legume endosymbiont rhizobium leguminosarum bv. viciae. these genes are clustered with 14 other genes including the hydrogenase structural genes hupsl. a set of isogenic mutants with in-frame deletions (deltahupg, deltahuph, deltahupi, and deltahupj) was generated and tested for hydrogenase activity in cultures grown at different oxygen concentrations (0.2 to 2.0%) and ... | 2005 | 16199572 |
| towards the identification of type ii secretion signals in a nonacylated variant of pullulanase from klebsiella oxytoca. | pullulanase (pula) from the gram-negative bacterium klebsiella oxytoca is a 116-kda surface-anchored lipoprotein of the isoamylase family that allows growth on branched maltodextrin polymers. pula is specifically secreted via a type ii secretion system. pelbsp-pula, a nonacylated variant of pula made by replacing the lipoprotein signal peptide (sp) with the signal peptide of pectate lyase pelb from erwinia chrysanthemi, was efficiently secreted into the medium. two 80-amino-acid regions of pula, ... | 2005 | 16199575 |
| role of the regulatory gene rira in the transcriptional response of sinorhizobium meliloti to iron limitation. | a regulatory network of sinorhizobium meliloti genes involved in adaptation to iron-limiting conditions and the involvement of the rhizobial iron regulator gene (rira) were analyzed by mutation and microarray analyses. a constructed s. meliloti rira mutant exhibited growth defects and enhanced h2o2 sensitivity in the presence of iron, but symbiotic nitrogen fixation was not affected. to identify iron-responsive and rira-regulated s. meliloti genes, a transcriptome approach using whole-genome mic ... | 2005 | 16204511 |
| tol-pal proteins are critical cell envelope components of erwinia chrysanthemi affecting cell morphology and virulence. | the tol-pal genes are necessary for maintaining the outer-membrane integrity of gram-negative bacteria. these genes were first described in escherichia coli, and more recently in several other species. they are involved in the pathogenesis of e. coli, haemophilus ducreyi, vibrio cholerae and salmonella enterica. the role of the tol-pal genes in bacterial pathogenesis was investigated in the phytopathogenic enterobacterium erwinia chrysanthemi, assuming that this organism might be a good model fo ... | 2005 | 16207916 |
| nonnatural amino acid incorporation into the methionine 214 position of the metzincin pseudomonas aeruginosa alkaline protease. | the alkaline protease from pseudomonas aeruginosa (apra) is a member of the metzincin superfamily of metalloendoproteases. a key feature of these proteases is a conserved methionine-containing 1,4-tight beta turn at the base of the active site zinc binding region. | 2005 | 16221305 |
| insights into genome plasticity and pathogenicity of the plant pathogenic bacterium xanthomonas campestris pv. vesicatoria revealed by the complete genome sequence. | the gram-negative plant-pathogenic bacterium xanthomonas campestris pv. vesicatoria is the causative agent of bacterial spot disease in pepper and tomato plants, which leads to economically important yield losses. this pathosystem has become a well-established model for studying bacterial infection strategies. here, we present the whole-genome sequence of the pepper-pathogenic xanthomonas campestris pv. vesicatoria strain 85-10, which comprises a 5.17-mb circular chromosome and four plasmids. th ... | 2005 | 16237009 |
| conserved role of the linker alpha-helix of the bacterial disulfide isomerase dsbc in the avoidance of misoxidation by dsbb. | in the bacterial periplasm the co-existence of a catalyst of disulfide bond formation (dsba) that is maintained in an oxidized state and of a reduced enzyme that catalyzes the rearrangement of mispaired cysteine residues (dsbc) is important for the folding of proteins containing multiple disulfide bonds. the kinetic partitioning of the dsba/dsbb and dsbc/dsbd pathways partly depends on the ability of dsbb to oxidize dsba at rates >1000 times greater than dsbc. we show that the resistance of dsbc ... | 2006 | 16280324 |
| identification of erwinia amylovora genes induced during infection of immature pear tissue. | the enterobacterium erwinia amylovora is a devastating plant pathogen causing necrotrophic fire blight disease of apple, pear, and other rosaceous plants. in this study, we used a modified in vivo expression technology system to identify e. amylovora genes that are activated during infection of immature pear tissue, a process that requires the major pathogenicity factors of this organism. we identified 394 unique pear fruit-induced (pfi) genes on the basis of sequence similarity to known genes a ... | 2005 | 16291682 |
| structural basis for shikimate-binding specificity of helicobacter pylori shikimate kinase. | shikimate kinase (ec 2.7.1.71) catalyzes the specific phosphorylation of the 3-hydroxyl group of shikimic acid in the presence of atp. as the fifth key step in the shikimate pathway for aromatic amino acid biosynthesis in bacteria, fungi, and plants, but not mammals, shikimate kinase represents an attractive target for the development of new antimicrobial agents, herbicides, and antiparasitic agents. here, we report the 1.8-angstroms crystal structure of helicobacter pylori shikimate kinase (hps ... | 2005 | 16291688 |
| a degenerate type iii secretion system from septicemic escherichia coli contributes to pathogenesis. | the type iii secretion system (t3ss) is an important virulence factor used by several gram-negative bacteria to deliver effector proteins which subvert host cellular processes. enterohemorrhagic escherichia coli o157 has a well-defined t3ss involved in attachment and effacement (ett1) and critical for virulence. a gene cluster potentially encoding an additional t3ss (ett2), which resembles the spi-1 system in salmonella enterica, was found in its genome sequence. the ett2 gene cluster has since ... | 2005 | 16291689 |
| identification of a twin-arginine translocation system in pseudomonas syringae pv. tomato dc3000 and its contribution to pathogenicity and fitness. | the bacterial plant pathogen pseudomonas syringae pv. tomato dc3000 (dc3000) causes disease in arabidopsis thaliana and tomato plants, and it elicits the hypersensitive response in nonhost plants such as nicotiana tabacum and nicotiana benthamiana. while these events chiefly depend upon the type iii protein secretion system and the effector proteins that this system translocates into plant cells, additional factors have been shown to contribute to dc3000 virulence and still many others are likel ... | 2005 | 16321949 |
| fermentation of 10% (w/v) sugar to d: (-)-lactate by engineered escherichia coli b. | derivatives of ethanologenic escherichia coli k011 were constructed for d: (-)-lactate production by deleting genes encoding competing pathways followed by metabolic evolution, a growth-based selection for mutants with improved performance. resulting strains, sz132 and sz186, contain native genes for sucrose utilization. no foreign genes are present in sz186. strain sz132 also contains a chromosomally integrated endoglucanase gene (erwinia chrysanthemi cely). strain sz132 produced over 1 mol lac ... | 2005 | 16328986 |
| alternative sigma factors and their roles in bacterial virulence. | sigma factors provide promoter recognition specificity to rna polymerase holoenzyme, contribute to dna strand separation, and then dissociate from the core enzyme following transcription initiation. as the regulon of a single sigma factor can be composed of hundreds of genes, sigma factors can provide effective mechanisms for simultaneously regulating expression of large numbers of prokaryotic genes. one newly emerging field is identification of the specific roles of alternative sigma factors in ... | 2005 | 16339734 |
| pectinmethylesterase from the rice weevil, sitophilus oryzae: cdna isolation and sequencing, genetic origin, and expression of the recombinant enzyme. | a cdna clone encoding pectinmethylesterase of the rice weevil, sitophilus oryzae (l.) has been isolated and sequenced. the cdna clone was expressed in cultured insect cells and active pectinmethylesterase was purified from the culture medium, thus confirming that the cdna encodes pectinmethylesterase. in situ hybridization indicated that the enzyme's transcript was present in the midgut. weevils treated with tetracycline so that they lack genes of known symbiotic organisms still contained the pe ... | 2005 | 16341253 |
| tn5-induced mutations in the enterobacterial phytopathogen erwinia chrysanthemi. | escherichia coli (2492/pjb4ji) matings with erwinia chrysanthemi produced kanamycin resistant (km) transconjugants, a majority of which were gentamicin sensitive (gm). a small proportion (about 0.8%) of the km gm clones were either auxotrophic or failed to catabolize galacturonate (gtu). the r plasmid (pjb4ji) dna was detected in the parent e. coli strain and in a km gm transconjugant, but not in km gme. chrysanthemi strains carrying tn5-induced mutations. in hfr crosses, km (tn5) was found link ... | 1983 | 16346212 |
| activity stain for rapid characterization of pectic enzymes in isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gels. | a system was developed for the rapid characterization of microbial pectic enzyme complexes and then tested on erwinia chrysanthemi and sclerotium rolfsii. pectic enzymes in minute samples of crude culture filtrates were resolved by ultrathin-layer polyacrylamide gel isoelectric focusing and sodium dodecyl sulfate-polyacrylamide gel electrophoresis and then assayed with an ultrathin pectate-agarose overlay stained with ruthenium red. the simple procedure can be completed within 30 min after isoel ... | 1985 | 16346881 |
| fermentation of d-xylose and l-arabinose to ethanol by erwinia chrysanthemi. | erwinia spp. are gram-negative facultative anaerobes within the family enterobacteriacae which possess several desirable traits for the conversion of pentose sugars to ethanol, such as the ability to ferment a broad range of carbohydrates and the ease with which they can be genetically modified. twenty-eight strains of erwinia carotovora and e. chrysanthemi were screened for the ability to ferment d-xylose to ethanol. e. chrysanthemi b374 was chosen for further study on the basis of its superior ... | 1987 | 16347426 |
| multiplication and virulence in plant tissues of escherichia coli clones producing pectate lyase isozymes plb and ple at high levels and of an erwinia chrysanthemi mutant deficient in ple. | the phytopathogenic enterobacterium erwinia chrysanthemi strain ec16 produces four isozymes of pectate lyase (pl), an extracellular enzyme that macerates parenchymatous plant tissues and kills plant cells. a 1.8-kilobase ecori dna fragment containing the entire pele gene was deleted from the e. chrysanthemi chromosome by marker exchange of a cloned fragment that had been modified in vitro. the resulting mutant, um1001, produced the isozymes pla, plb, and plc, but not ple. mutant um1001 was compa ... | 1987 | 16347452 |
| erwinia chrysanthemi ec16 produces a second set of plant-inducible pectate lyase isozymes. | the enterobacterium erwinia chrysanthemi causes soft-rot diseases involving extensive tissue maceration in a wide variety of plants and secretes multiple pectic enzymes that degrade plant cell walls and middle lamellae. an e. chrysanthemi mutant with directed deletions or insertions in genes pehx, pelx, pela, pelb, pelc, and pele, which encode exo-poly-alpha-d-galacturonosidase, exopolygalacturonate lyase, and four isozymes of pectate lyase, respectively, was constructed by the marker exchange o ... | 1993 | 16348952 |
| two genomic regions involved in catechol siderophore production by erwinia carotovora. | two regions involved in catechol biosynthesis (cbs) of erwinia carotovora w3c105 were cloned by functional complementation of escherichia coli mutants that were deficient in the biosynthesis of the catechol siderophore enterobactin (ent). a 4.3-kb region of genomic dna of e. carotovora complemented the entb402 mutation of e. coli. a second genomic region of 12.8 kb complemented entd, entc147, ente405, and enta403 mutations of e. coli. although functions encoded by catechol biosynthesis genes (cb ... | 1994 | 16349193 |
| ribotyping of erwinia chrysanthemi strains in relation to their pathogenic and geographic distribution. | 16s and 23s rrnas from escherichia coli were used to study the relationship among a representative collection of strains of erwinia chrysanthemi differing in their original host and geographical origin. phenetic analysis of restriction fragment length polymorphisms allowed the distribution of the studied strains into seven clusters. these clusters were similar to those obtained by cladistic methods and appeared to correlate well with the established pathovars and biovars but to a lesser extent w ... | 1994 | 16349416 |
| formation of the blue pigment indigoidine by phytopathogenic erwinia. | most cultures belonging to the "erwinia chrysanthemi group" of soft-rot bacteria form traces of a blue, extracellular, water-insoluble pigment. this pigment is generally not found in cultures of the other members of the genus erwinia. the blue substance has been isolated and purified from three members of the e. chrysanthemi group; it has been identified as indigoidine, 5,5'-diamino-4,4'-dihydroxy-3,3'-diazadiphenoquinone-(2,2'). | 1966 | 16349687 |
| comparative and functional genomic analysis of prokaryotic nickel and cobalt uptake transporters: evidence for a novel group of atp-binding cassette transporters. | the transition metals nickel and cobalt, essential components of many enzymes, are taken up by specific transport systems of several different types. we integrated in silico and in vivo methods for the analysis of various protein families containing both nickel and cobalt transport systems in prokaryotes. for functional annotation of genes, we used two comparative genomic approaches: identification of regulatory signals and analysis of the genomic positions of genes encoding candidate nickel/cob ... | 2006 | 16352848 |
| pecs and pect coregulate the synthesis of hrpn and pectate lyases, two virulence determinants in erwinia chrysanthemi 3937. | erwinia chrysanthemi strain 3937 is a necrotrophic bacterial plant pathogen. pectinolytic enzymes and, in particular, pectate lyases play a key role in soft rot symptoms; however, the efficient colonization of plants by e. chrysanthemi requires additional factors. these factors include hrpn (harpin), a heat-stable, glycine-rich hydrophilic protein, which is secreted by the type iii secretion system. we investigated the expression of hrpn in e. chrysanthemi 3937 in various environmental condition ... | 2005 | 16353555 |
| asap: a resource for annotating, curating, comparing, and disseminating genomic data. | asap is a comprehensive web-based system for community genome annotation and analysis. asap is being used for a large-scale effort to augment and curate annotations for genomes of enterobacterial pathogens and for additional genome sequences. new tools, such as the genome alignment program mauve, have been incorporated into asap in order to improve display and analysis of related genomes. recent improvements to the database and challenges for future development of the system are discussed. asap ... | 2006 | 16381899 |
| asap: a resource for annotating, curating, comparing, and disseminating genomic data. | asap is a comprehensive web-based system for community genome annotation and analysis. asap is being used for a large-scale effort to augment and curate annotations for genomes of enterobacterial pathogens and for additional genome sequences. new tools, such as the genome alignment program mauve, have been incorporated into asap in order to improve display and analysis of related genomes. recent improvements to the database and challenges for future development of the system are discussed. asap ... | 2006 | 16381899 |
| cytochrome p450 alkane hydroxylases of the cyp153 family are common in alkane-degrading eubacteria lacking integral membrane alkane hydroxylases. | several strains that grow on medium-chain-length alkanes and catalyze interesting hydroxylation and epoxidation reactions do not possess integral membrane nonheme iron alkane hydroxylases. using pcr, we show that most of these strains possess enzymes related to cyp153a1 and cyp153a6, cytochrome p450 enzymes that were characterized as alkane hydroxylases. a vector for the polycistronic coexpression of individual cyp153 genes with a ferredoxin gene and a ferredoxin reductase gene was constructed. ... | 2006 | 16391025 |
| a selc-associated genomic island of the extraintestinal avian pathogenic escherichia coli strain ben2908 is involved in carbohydrate uptake and virulence. | the complete nucleotide sequence and genetic organization of a new genomic island (agi-3) isolated from the extraintestinal avian pathogenic escherichia coli strain ben2908 is reported. this 49,600-bp island is inserted at the selc locus and contains putative mobile genetic elements such as a phage-related integrase gene, transposase genes, and direct repeats. agi-3 shows a mosaic structure of five modules. some of these modules are present in other e. coli strains and in other pathogenic bacter ... | 2006 | 16428402 |
| characterization of the biosynthetic pathway of glucosylglycerate in the archaeon methanococcoides burtonii. | the pathway for the synthesis of the organic solute glucosylglycerate (gg) is proposed based on the activities of the recombinant glucosyl-3-phosphoglycerate synthase (gpgs) and glucosyl-3-phosphoglycerate phosphatase (gpgp) from methanococcoides burtonii. a mannosyl-3-phosphoglycerate phosphatase gene homologue (mpgp) was found in the genome of m. burtonii (http://www.jgi.doe.gov), but an mpgs gene coding for mannosyl-3-phosphoglycerate synthase (mpgs) was absent. the gene upstream of the mpgp ... | 2006 | 16428406 |
| calcium-regulated type iii secretion of yop proteins by an escherichia coli hha mutant carrying a yersinia pestis pcd1 virulence plasmid. | a series of four large deletions that removed a total of ca. 36 kb of dna from the ca. 70-kb yersinia pestis pcd1 virulence plasmid were constructed using lambda red-mediated recombination. escherichia coli hha deletion mutants carrying the virulence plasmid with the deletions expressed a functional calcium-regulated type iii secretion system. the e. coli hha/pcd1 system should facilitate molecular studies of the type iii secretion process. | 2006 | 16428789 |
| keeping their options open: acute versus persistent infections. | 2006 | 16452401 | |
| lbta and lbtb are required for production of the legionella pneumophila siderophore legiobactin. | under iron stress, legionella pneumophila secretes legiobactin, a nonclassical siderophore that is reactive in the chrome azurol s (cas) assay. here, we have optimized conditions for legiobactin expression, shown its biological activity, and identified two genes, lbta and lbtb, which are involved in legiobactin production. lbta appears to be iron repressed and encodes a protein that has significant homology with siderophore synthetases, and frga, a previously described iron-regulated protein of ... | 2006 | 16452417 |
| molecular cloning of erwinia chrysanthemi pectinase and cellulase structural genes. | erwinia chrysanthemi 3937 secretes four major pectate lyase isoenzymes (pl, ec 4.2.2.2) and one endocellulase (cx, ec 3.2.1.4). a genomic library of this strain was constructed in the lambda l47-1 vector, and screened for the presence of pl and cx on pectate and caboxymethylcellulose agar. among the seven cx-positive phage clones, three were shown to encode an enzyme of the same mol. wt. as the one found in the culture supernatant of strain 3937. the 34 pl-positive phage clones were analyzed by ... | 1985 | 16453606 |
| in vivo cloning of the pectate lyase and cellulase genes of erwinia chrysanthemi. | using an rp4 plasmid which carries a mini-mu prophage which allows it to integrate spontaneously random pieces of its host chromosome, we cloned in vivo at least some of the pectate lyase and cellulase genes of the erwinia chrysanthemi strain b374. the rp4-prime plasmids were used to localize the cloned genes on the b374 chromosome by co-transposition mapping and to subclone most of the genes in a classic high copy number plasmid vector. | 1985 | 16453607 |
| within-species flagellin polymorphism in xanthomonas campestris pv campestris and its impact on elicitation of arabidopsis flagellin sensing2-dependent defenses. | bacterial flagellins have been portrayed as a relatively invariant pathogen-associated molecular pattern. we have found within-species, within-pathovar variation for defense-eliciting activity of flagellins among xanthomonas campestris pv campestris (xcc) strains. arabidopsis thaliana flagellin sensing2 (fls2), a transmembrane leucine-rich repeat kinase, confers flagellin responsiveness. the flg22 region was the only xcc flagellin region responsible for detectable elicitation of arabidopsis defe ... | 2006 | 16461584 |
| identification of genes associated with survival of salmonella enterica serovar enteritidis in chicken egg albumen. | salmonella enterica consists of over 2,000 serovars that are major causes of morbidity and mortality associated with contaminated food. despite similarities among serovars of salmonella enterica, many demonstrate unique host specificities, epidemiological characteristics, and clinical manifestations. one of the unique epidemiological characteristics of the serovar enteritidis is that it is the only bacterium routinely transmitted to humans through intact chicken eggs. therefore, salmonella enter ... | 2006 | 16461649 |
| biocontrol of the food-borne pathogens listeria monocytogenes and salmonella enterica serovar poona on fresh-cut apples with naturally occurring bacterial and yeast antagonists. | fresh-cut apples contaminated with either listeria monocytogenes or salmonella enterica serovar poona, using strains implicated in outbreaks, were treated with one of 17 antagonists originally selected for their ability to inhibit fungal postharvest decay on fruit. while most of the antagonists increased the growth of the food-borne pathogens, four of them, including gluconobacter asaii (t1-d1), a candida sp. (t4-e4), discosphaerina fagi (st1-c9), and metschnikowia pulcherrima (t1-e2), proved ef ... | 2006 | 16461659 |
| participation of a galactose-specific c-type lectin in drosophila immunity. | a galactose-specific c-type lectin has been purified from a pupal extract of drosophila melanogaster. this lectin gene, named dl1 (drosophila lectin 1), is part of a gene cluster with the other two galactose-specific c-type lectin genes, named dl2 (drosophila lectin 2) and dl3 (drosophila lectin 3). these three genes are expressed differentially in fruit fly, but show similar haemagglutinating activities. the present study characterized the biochemical and biological properties of the dl1 protei ... | 2006 | 16475980 |
| changes in hypercoagulability by asparaginase: a randomized study between two asparaginases. | alterations in hemostasis have frequently been observed in children with acute lymphoblastic leukemia. thrombotic events are well documented in patients receiving l-asparaginase as a single agent or in combination with other chemotherapeutic drugs. the present prospective, randomized study evaluated the effect of two different l-asparaginase preparations, native escherichia coli l-asparaginase (crasnitin; bayer ag, leverkusen, germany; n = 10) and l-asparaginase derived from erwinia chrysanthemi ... | 2006 | 16479196 |
| rhizobial exopolysaccharides: genetic control and symbiotic functions. | specific complex interactions between soil bacteria belonging to rhizobium, sinorhizobium, mesorhizobium, phylorhizobium, bradyrhizobium and azorhizobium commonly known as rhizobia, and their host leguminous plants result in development of root nodules. nodules are new organs that consist mainly of plant cells infected with bacteroids that provide the host plant with fixed nitrogen. proper nodule development requires the synthesis and perception of signal molecules such as lipochitooligosacchari ... | 2006 | 16483356 |
| health considerations regarding horizontal transfer of microbial transgenes present in genetically modified crops. | the potential effects of horizontal gene transfer on human health are an important item in the safety assessment of genetically modified organisms. horizontal gene transfer from genetically modified crops to gut microflora most likely occurs with transgenes of microbial origin. the characteristics of microbial transgenes other than antibiotic-resistance genes in market-approved genetically modified crops are reviewed. these characteristics include the microbial source, natural function, function ... | 2005 | 16489267 |
| crystallization and preliminary crystallographic analysis of l-asparaginase from erwinia carotovora. | bacterial l-asparaginases have been used as therapeutic agents in the treatment of acute childhood lymphoblastic leukaemia for over 30 y. however, their use is limited owing to the glutaminase activity of the administered enzymes, which results in serious side effects. in contrast, l-asparaginase from erwinia carotovora exhibits low glutaminase activity at physiological concentrations of l-asparagine and l-glutamine in the blood. recombinant er. carotovora l-asparaginase was crystallized in the ... | 2005 | 16511054 |
| harpin mediates cell aggregation in erwinia chrysanthemi 3937. | the hypersensitive response elicitor harpin (hrpn) of soft rot pathogen erwinia chrysanthemi strains 3937 and ec16 is secreted via the type iii secretion system and remains cell surface bound. strain 3937 hrpn is essential for cell aggregation, but the c-terminal one-third of the protein is not required for aggregative activity. | 2006 | 16513758 |
| the phytopathogen dickeya dadantii (erwinia chrysanthemi 3937) is a pathogen of the pea aphid. | dickeya dadantii (erwinia chrysanthemi) is a phytopathogenic bacterium causing soft rot diseases on many crops. the sequencing of its genome identified four genes encoding homologues of the cyt family of insecticidal toxins from bacillus thuringiensis, which are not present in the close relative pectobacterium carotovorum subsp. atrosepticum. the pathogenicity of d. dadantii was tested on the pea aphid acyrthosiphon pisum, and the bacterium was shown to be highly virulent for this insect, either ... | 2006 | 16517643 |
| differentiation of species combined into the burkholderia cepacia complex and related taxa on the basis of their fatty acid patterns. | using the established commercial system sherlock (midi, inc.), cellular fatty acid methyl ester analysis for differentiation among burkholderia cepacia complex species was proven. the identification key based on the diagnostic fatty acids is able to discern phenotypically related ralstonia pickettii and pandoraea spp. and further distinguish burkholderia pyrrocinia, burkholderia ambifaria, and burkholderia vietnamiensis. | 2006 | 16517920 |
| xpse oligomerization triggered by atp binding, not hydrolysis, leads to its association with xpsl. | gspe belongs to a secretion ntpase superfamily, members of which are involved in type ii/iv secretion, type iv pilus biogenesis and dna transport in conjugation or natural transformation. predicted to be a cytoplasmic protein, gspe has nonetheless been shown to be membrane-associated by interacting with the n-terminal cytoplasmic domain of gspl. by taking biochemical and genetic approaches, we observed that atp binding triggers oligomerization of xanthomonas campestris xpse (a gspe homolog) as w ... | 2006 | 16525507 |
| domain-based small molecule binding site annotation. | accurate small molecule binding site information for a protein can facilitate studies in drug docking, drug discovery and function prediction, but small molecule binding site protein sequence annotation is sparse. the small molecule interaction database (smid), a database of protein domain-small molecule interactions, was created using structural data from the protein data bank (pdb). more importantly it provides a means to predict small molecule binding sites on proteins with a known or unknown ... | 2006 | 16545112 |
| identification of the substrate interaction region of the chitin-binding domain of streptomyces griseus chitinase c. | chitinase c from streptomyces griseus hut6037 was discovered as the first bacterial chitinase in family 19 other than chitinases found in higher plants. chitinase c comprises two domains: a chitin-binding domain (chbd(chic)) for attachment to chitin and a chitin-catalytic domain for digesting chitin. the structure of chbd(chic) was determined by means of 13c-, 15n-, and 1h-resonance nuclear magnetic resonance (nmr) spectroscopy. the conformation of its backbone comprised two beta-sheets composed ... | 2006 | 16567413 |
| the erwinia chrysanthemi 3937 phoq sensor kinase regulates several virulence determinants. | the phopq two-component system regulates virulence factors in erwinia chrysanthemi, a pectinolytic enterobacterium that causes soft rot in several plant species. we characterized the effect of a mutation in phoq, the gene encoding the sensor kinase phoq of the phopq two-component regulatory system, on the global transcriptional profile of e. chrysanthemi using cdna microarrays and further confirmed our results by quantitative reverse transcription-pcr analysis. our results indicate that a mutati ... | 2006 | 16585768 |
| psychrophilic microorganisms: challenges for life. | the ability of psychrophiles to survive and proliferate at low temperatures implies that they have overcome key barriers inherent to permanently cold environments. these challenges include: reduced enzyme activity; decreased membrane fluidity; altered transport of nutrients and waste products; decreased rates of transcription, translation and cell division; protein cold-denaturation; inappropriate protein folding; and intracellular ice formation. cold-adapted organisms have successfully evolved ... | 2006 | 16585939 |
| impaired induction and self-catabolite repression of extracellular pectate lyase in erwinia chrysanthemi mutants deficient in oligogalacturonide lyase. | the pectate lyase (pl; ec 4.2.2.2) secreted by the plant pathogen erwinia chrysanthemi is induced and catabolite repressed by different concentrations of its own product, digalacturonic acid 4,5-unsaturated at the nonreducing end [u(galua)(2)]. both activities of u(galua)(2) depend on its cleavage by oligogalacturonide lyase (ogl; ec 4.2.2.6). this intracellular enzyme converts u(galua)(2) to the deoxyketuronic acid 4-deoxy-l-threo-5-hexosulose uronic acid, which is then isomerized to 3-deoxy-d- ... | 1981 | 16593039 |
| population behavior analysis of dspe and peld regulation in erwinia chrysanthemi 3937. | erwinia chrysanthemi 3937 (ech3937) is a phytopathogenic bacterium with a wide host range. the pectinolytic enzymes secreted by the bacterium and the type iii secretion system (t3ss) are essential for full virulence. we used the green fluorescent protein gene as a reporter to investigate the expression of dspe (a putative t3ss effector) and peld (a major pectin-degrading enzyme) in populations of ech3937 under different conditions. gene expression was analyzed by measuring the fluorescence inten ... | 2006 | 16610748 |
| lrha regulates rpos translation in response to the rcs phosphorelay system in escherichia coli. | regulation of the escherichia coli stationary-phase sigma factor rpos is complex and occurs at multiple levels in response to different environmental stresses. one protein that reduces rpos levels is the transcription factor lrha, a global regulator of flagellar synthesis. here we clarify the mechanism of this repression and provide insight into the signaling pathways that feed into this regulation. we show that lrha represses rpos at the level of translation in a manner that is dependent on the ... | 2006 | 16621809 |
| regulatory roles for isca and sufa in iron homeostasis and redox stress responses in the cyanobacterium synechococcus sp. strain pcc 7002. | sufa, isca, and nfu have been proposed to function as scaffolds in the assembly of fe/s clusters in bacteria. to investigate the roles of these proteins further, single and double null-mutant strains of synechococcus sp. strain pcc 7002 were constructed by insertional inactivation of genes homologous to sufa, isca, and nfu. demonstrating the nonessential nature of their products, the sufa, isca, and sufa isca mutants grew photoautotrophically with doubling times that were similar to the wild typ ... | 2006 | 16621810 |
| thin aggregative fimbriae and cellulose enhance long-term survival and persistence of salmonella. | salmonella spp. are environmentally persistent pathogens that have served as one of the important models for understanding how bacteria adapt to stressful conditions. however, it remains poorly understood how they survive extreme conditions encountered outside their hosts. here we show that the rdar morphotype, a multicellular phenotype characterized by fimbria- and cellulose-mediated colony pattern formation, enhances the resistance of salmonella to desiccation. when colonies were stored on pla ... | 2006 | 16621814 |